Investigations On The Functionalized Polymers For The Isolation/purification Of Proteins

This thesis includes two parts. In the first part, we prepared a poly(N-isopropylacrylamide-co-acrylic acid) hydrogel by performing the polymerization in an soap free aqueous emulsion. The obtained hydrogel exhibits sensitive and rapid response to pH value due to the abundant-COOH groups on its surface. The performance of this hydrogel in the isolation/purification of proteins was studied and the experimental results indicated that selective adsorption of hemoglobin could be achieved using this hydrogel as sorbent. With a pH value of6.0, an adsorption efficiency of93%was obtained for1mL of200μg mL-1hemoglobin, by using2mg hydrogel as sorbent with a sorption time of20min. The adsorbed hemoglobin could be readily stripped by a Tris-HCl buffer of pH8.6, giving rise to an elution efficiency of76%. A solid-phase extraction protocol was thus developed for the isolation of hemoglobin from human blood and the results of SDS-PAGE suggested that high purity hemoglobin was obtained.The second part of the thesis includes the preparation and application of a poly ionic liquid (Poly(ViEtIm+Br-)). The poly ionic liquid was immobilized onto the surface of carbon nano-tubes to obtain a solid phase composite. A sequential-injection on-line protocol was developed for the isolation/purification of serum album using the composite as sorbent. With a sample volume of2mL and a sample pH value of5.2, an adsorption efficiency of91%was achieved. The absorbed protein was effectively eluted by using a citrate buffer (0.04mol L-1). The time required for the on-line isolation/purification was500s and an enrichment factor of5was achieved for serum album. The practical applicability of this on-line protocol was demonstrated by processing human whole blood for the isolation and enrichment of HSA, and satisfactory results were obtained by assay with SDS-PAGE.